This proposal is a competitive renewal of MH44801 (The Epidemiology of Newly Diagnosed Psychotic Disorders), an epidemiologic study of first-admission patients drawn from all of the inpatient facilities in Suffolk County, New York. The aims are to complete the follow-up assessments and consensus diagnoses of the cohort and to conduct analyses on the stability of diagnosis in the early course of illness, diagnostic differences in illness characteristics and 4-year course, the utility of a modified vulnerability model to explain course and outcome, differential effects of treatment experiences over the 48-month follow-up, and the natural history of disorder in special groups (poor cognitive functioning; HIV +; early deficit syndrome; brief psychoses; youth with psychotic affective disorders). Multiple indicators of functioning, and a comprehensive set of predictors, are included. The design entailed baseline assessments (usually before discharge) and face-to-face follow-up 6, 24-, and 48-months later with brief contact every 3 months through 24-months and every 6 months thereafter. Consensus diagnoses were formulated after the baseline, 6- and 24-month assessments; respondents with unclear or shifting diagnoses were reviewed again after the 48-month interview. Significant other interviews and ancillary medical information were also obtained longitudinally. From 1989-1995, 733 respondents were interviewed at baseline (response rate=72%). Of the 471 patients referred to the study from 1989-92, 355 agreed to a baseline interview (75.4%). We retained 94.5% of qualified respondents at 6-months, and 89.3% of qualified respondents at 24-months (including 94.8% of 6-month respondents). Considerable effort has gone into the field work and DSM-III-R and DSM-IV diagnostic formulations over the past several years. The interviewers are psychiatric social workers, and the data collection includes psychiatric, psychosocial, and neuropsychological assessments. Project psychiatrists formulating the diagnoses include senior faculty as well as fellows hired specifically for the study. In addition, we conducted preliminary analyses with respondents enrolled in the study during the first few years. This resulted in a number of methodological and substantive publications on diagnostic issues (stability during the first 6 months; unclear diagnoses; brief psychoses; discharge vs. research diagnosis), affective disorders, predictors of early course, differences at baseline between respondents who revealed full vs. partial or no psychotic symptoms during the interview, and negative symptoms. Using this first-phase sample, we are currently completing a set of papers on the 24-month course experience, diagnostic shifts, and the characteristics of special sub-populations. During the renewal period, we also plan to keep track of the sample to prepare for future research.